I am in the market for the fastest bike I can get in the $900-$1500 dollar range. To give you an idea I am thinking, I'm leaning towards the Specialized stumpjumper but am also looking at : Trek 8000; GF Hoo Koo E Koo; GF Big Sur; GF X-Caliber; Giant XtC 2. Any input about other bikes to consider or on the ones listed above?

^
Indeed. Vertex 30 is a heckuva bike for the money and should run about $1200 or so. Handbuilt quality, bodacious frame, and not everyone has one.
Fishers are nice, if the geometry works for you. X-Caliber will be very different from the KHEK or Big Sur as it is a 29'er.
Bottom line is you need to ride as many bikes as you can within your price range and decide which one you like best-that's the important part.
As to the fastest bike among those, that depends on you, my friend.

thats awesome, when it's my turn to go looking for a ~1000 bike, I will definitely have to consider one. My bike now handles great compared to my friends bike, so that is a very important point for me anyway.

I did a lot of research on bikes in your price range.
I bought a Cannondale F600 (the SL comes without disc brakes you can probalby find this bike for under $1k; with disc brakes it's about $100 more).
It has a great frame. Decent components. Great suspension lock out feature. Handles like a dream and responds well to climbs.

The other bikes you listed are pretty good, but if you don't at least look into a Cannondale you're selling yourself short.